title: ATR acts stage specifically to regulate multiple aspects of mammalian meiotic silencing.
abstract: In mammals, homologs that fail to synapse during meiosis are transcriptionally inactivated. This process, meiotic silencing, drives inactivation of the heterologous XY bivalent in male germ cells (meiotic sex chromosome inactivation [MSCI]) and is thought to act as a meiotic surveillance mechanism. The checkpoint protein ATM and Rad3-related (ATR) localizes to unsynapsed chromosomes, but its role in the initiation and maintenance of meiotic silencing is unknown. Here we show that ATR has multiple roles in silencing. ATR first regulates HORMA (Hop1, Rev7, and Mad2) domain protein HORMAD1/2 phosphorylation and localization of breast cancer I (BRCA1) and ATR cofactors ATR-interacting peptide (ATRIP)/topoisomerase 2-binding protein 1 (TOPBP1) at unsynapsed axes. Later, it acts as an adaptor, transducing signaling at unsynapsed axes into surrounding chromatin in a manner that requires interdependence with mediator of DNA damage checkpoint 1 (MDC1) and H2AFX. Finally, ATR catalyzes histone H2AFX phosphorylation, the epigenetic event leading to gene inactivation. Using a novel genetic strategy in which MSCI is used to silence a chosen gene in pachytene, we show that ATR depletion does not disrupt the maintenance of silencing and that silencing comprises two phases: The first is dynamic and reversible, and the second is stable and irreversible. Our work identifies a role for ATR in the epigenetic regulation of gene expression and presents a new technique for ablating gene function in the germline.
authors.affiliation: Division of Stem Cell Biology and Developmental Genetics, Medical Research Council, National Institute for Medical Research, London NW7 1AA, United Kingdom;
authors.forename: Hélène
authors.initials: H
authors.lastname: Royo
authors.forename: Haydn
authors.initials: H
authors.lastname: Prosser
authors.forename: Yaroslava
authors.initials: Y
authors.lastname: Ruzankina
authors.forename: Shantha K
authors.initials: SK
authors.lastname: Mahadevaiah
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Cloutier
authors.forename: Marek
authors.initials: M
authors.lastname: Baumann
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Fukuda
authors.forename: Christer
authors.initials: C
authors.lastname: Höög
authors.forename: Attila
authors.initials: A
authors.lastname: Tóth
authors.forename: Dirk G
authors.initials: DG
authors.lastname: de Rooij
authors.forename: Allan
authors.initials: A
authors.lastname: Bradley
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Brown
authors.forename: James M A
authors.initials: JM
authors.lastname: Turner
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism*; D002875:Chromosomes / Q000378:metabolism; D005786:Gene Expression Regulation; D020868:Gene Silencing; D006657:Histones / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D008540:Meiosis; D051379:Mice; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism*; D021381:Protein Transport / Q000235:genetics; D012097:Repressor Proteins / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D017346:Protein Serine-Threonine Kinases; D012097:Repressor Proteins; C508937:MDC1 protein, mouse; C576897:Atr protein, mouse; C475961:gamma-H2AX protein, mouse
keywords: ATR; meiosis; sex chromosomes